Emergency control device



y H. J. VENARD 1,967,521

EMERGENCY CONTROL DEVICE Filed April 13. 1931 Patented July 24, 1934EMERGENCY oomor. navron Harold J. Venanl. Chicago, 111. ApplicationApril 1:, 1931', Serial him-529,585

'lGlaims.

This invention relates generally to emergencycontrol devices operativeto assume temporarily the function of a primary electric element in thee'vent of failure of such element to perform its intended function. I v

I More particularly, the invention is adapted for use in connection withelectric elements which in operation generate heat, such as lampsrequired to furnish illumination continuously, such as beacon, emergencyor exit lights; and the primary object of the invention is to provide anemergency control device including a thermally responsive switchcontrolled by the primary electric element and operative upon thefailure of the latter to render operative a secondary or auxiliaryelement of similar character until such time as the main element iscaused to resume its normal operation. A further object of the inventionis to provide an electric lighting device having main and auxiliarylamps or bulbs in combination with a thermostatically actuated switchfor controlling the operation of the auxiliary bulb.

. Another object of this invention is the direct control of the circuitof the auxiliary bulb by means responsive to the radiation of heat fromthe main bulb.

A further object of this invention is to adapt a thermostaticallycontrolled device of the character described to bulbs of varyingcapacity by the provision of means for adjustingthe thermostatic controlmeans.

Other objects and advantages will become apparent from the followingdetailed description '35 taken in connection with the accompanyingvdrawing, in which:

Figure 1 is an elevational view of a device embodying the features ofthis invention.

Fig. 2 is a view partially in section and partially broken away to showthe circuit of the device and the construction of the thermostaticswitch.

While the invention is adapted for a variety of installations of varyingtype and size, it is here shown and will be described in an exemplaryembodiment adapted for use in exit lights required in public buildings,threatres and the like. City ordinances usually require that exit lightsshould be maintained burning continually and compliance with theordinance when an electrical lighting system is employed is hereaccomplished by the provision 01' a device having a plurality of bulbswith thermo-responsive means exposed to the heat of the bulbs andconnected directly in thecircuits of the bulbs in a manner to maintainbut one bulb lighted at all times. Such direct control of the circuitsinsuring proper operation of the device under all conditions andmaterially simplifying the construction. 6.

In the exemplary embodiment illustrated in the drawing, the body of thedevice consists of an insulating casing 3 shaped to form a pair ofbulbreceiving sockets 4 and 5 having a conducting lining 6 similar tothe ordinary two-bulb 65 attachment plug. Projecting from the base ofthe casing 3 are two contact prongs 7 and 8 adapted to be inserted in awall outlet for con- 'nection with the supply lines. The prong 'l vextends through the base of the casing (see Fig. 2) into contact withstrips: 9 which are an integral part of thelinings 6 of both sockets.The prong 8 is in electrical'contact with a strip 10, terminating in thecenter of the socket 4 to v 7 form a contact10=, by means-of a bolt 11projecting through the base of the ca'singi Turned into the socket 4into engagement with the contact 10" is a bulb 12, hereafter designatedas the main bulb, which is thus permanently connected in circuit withthe prongs 3 7 and 8 through the strip 9, the lining 6 and the strip 10.The bulb will thus always be supplied with current whenever the plug isinserted into the wall outlet or other termination oi. the supply wiresand as long as the bulb is in good con- 35 dition will be lighted.

Turned into the socket 5 is a bulb 13, hereafterldesignated theauxiliary bulb, which is .to be connected to the supply lines in case offailure of the main bulb. The auxiliary bulb 13 is con- .96 nected tothe prong 7 through the lining 6 and strip 9 just as is the main bulb,but is connected to the prong 8 by means of a lead 14 outside of thecasing connected at its ends to a contact 15 and the strip 10. It isthus apparent that the main and auxiliary bulbs are connected inparallel and may be lighted independently.

To insure a lighting of the auxiliary bulb at the proper times meansresponsive to the heat of the main bulb is employed to control directly,that is, without the aid of other mechanical or electrical devices, thecircuit of the auxiliary bulb. In the present instance this meansconsists of a thermostatic switch 16 positioned adjacent the main bulband connected in series with the auxiliary bulb. The switch 16 is hereinformed by two bimetallic thermal elements 1'1 and 18 connected in thelead 14 and disposed in linear relationship in a semi-tubularprotectcasing 19 of insulating material so that sub- Y 'Qelements, ms

stantially the entire length of both is exposed directly to the heat ofthe bulb. The thermal elements are rigidly secured at their extreme endsto the casing 19 in a manner to contact at 5 their inner ends with adegree of tension when cold and to flex away from each other whenexposed to heat. Thus when the light is first turned on both the mainand the auxiliary bulb will burn. However, after a short time the heatfrom the main bulb will flex the thermal elements sufllciently to openthe switch 16 thereby breaking the circuit of the auxiliary bulb. Shouldthe main bulb burn out the elements will cool and return to normalposition thereby com- 1 pleting the circuit through the auxiliary bulband causing it to light.

The casing 19 enclosing the thermal elements 17 and 18 is preferablyremovably attached to the bulb 12 by means of a spring clip 20 toiacilitate replacement of the bulb.

It is desirable that the auxiliary bulb be lighted within a minimumperiod of time after failure of the main bulb and to accomplish this theelements of the switch 16 are adjusted to be flexed by the heat of thebulb just sufllciently to open the switch 16. Only a slight cooling ofthe elements is thus necessary to close the switch 16 which will occurimmediately upon failure of the main bulb. With a permanent adjustmentof the elements of the switch 16 it is apparent that the switch would beadapted for satisfactory use only with a bulb of a certain capacity; asmaller bulb being incapable of opening the switch and a larger bulbflexing the 35 elements so far as to cause undesirable delay in thelighting of the auxiliary bulb upon failure of the main bulb. I

To facilitate the initial positioning of the elements and to adapt thedevice-tor use with bulbs of different capacity means .to'radjusting theswitch to open at different intensitlesof heat is provided. This means'colisistssiinply of a bolt 21 projecting throughthe casing .19 andthread- -ed into a nut -'22 rigid onthe' element 18. By turning the bolt'21 t6 fleie 'the element 18 in a manner tdidegr ase the tension'betweenthe two ward'i the; casing 19, less heat M nF theswitch while if the ,thother way more heat will will be requ re bolt 21 ,istujrn,

, be required; The; device may thus be convenientlyeiadiustedffor usewith any size of bulb.

I' claim as my invention: 1. In an electric lighting device, a main bulb5 adapted to be normally lighted, an auxiliary bulb in parallel withsaid main bulb, a socket for each of said bulbs, and a thermo-responsiveswitch in series with said auxiliary bulb, said switch being mountedadjacent said main bulb and adapted to be maintained open by the heat ofthe lighted main bulb but closing the circuit through said auxili rybulb when said mainbulb rails to light.

2..An electric lighting device comprising, in combination, a main bulb,sockets wherein said bulbs are mounted, an auxiliary bulb, an electriccircuit connecting each of said bulbs to a source 01' energy, meansincluding a bimetallic thermal elementrorming a switch connected inseries with said auxiliary bulb, and a protecting casing carrying saidelements removably mounted on the main bulb, said elements when coldbeing in use with bulbs of different electrical capacity.

iliary bulb and flexing in opposite directions to break the circuit whenexposed to the heat of said main bulb.

3. An electric lighting device, comprising, in

combination, a main bulb, an auxiliary bulb,

sockets wherein said bulbs are mounted, an electric circuit connectingeach or said bulbs to a source of energy, a theme-responsive switchpositioned so as to be exposed to the heat of said main bulb andconnected in series with said all!- iliary bulb, said switch beingadapted to. break the circuit when said main bulb is burning, and meansfor adjusting said switch to adapt it for 4. An electric lightingdevice, comprising, in combinationfa main bulb, an auxiliary bulb,sockets wherein said bulbs are mounted, an electric circuit connectingeach of said bulbs to a source of energy,and thermo-responsive meansmounted adjacent said main bulb controlling'the circuit of saidauxiliary bulb comprising a pair of bimetallic thermal elements mountedto form a switchand connected inseries with the auxiliary bulb, said.elements being normally in contact but flexing in opposite directionsupon exposure to heat from said main bulb to break the circuit of saidauxiliary bulb, and means for adjusting said elements to 'vary theintensity of heat required to open the switch.

5. An electric lighting device comprising, in combination, a main bulb,an auxiliary bulb, sockets wherein said bulbs are mounted, an electriccircuit connecting each of said bulbs to a source of energy, a pair ofbimetallic thermal elements forming a switch connected in series withsaid auxiliary bulb, and a mounting for said elements supporting themadjacent said main bulb, said elements being arranged in linearrelationship to increase the sensitivity ,of the switch'by exposure ofboth elements directly to the heat 0! said main bulb.

6. The combination with main and auxiliary lamps, of means providing twocircuits respectively including said lamps for connecting them with asource of electric energy, one of said circuits being constantly closedand operative to effect a continuous supply of energy from said sourceto the main lamp, said other circuit including a switch, and a thermaldevice responsive to the heat of the main lamp and operative to opensaid switch when the main lamp is in operation and to close saidswitchautomatically upon failure of the main lamp.

7. The combination with main and auxiliary lamps of a. casing structureof insulating material providing sockets for respectively receiving saidlamps and having two terminals adapted for connection with a source ofelectric energy, means in said casing structure providing two circuitsrespectively including the main and auxiliary lamps for connecting themto said terminals, one of saidcircuits being constantly operative toeffect a continuous supply of energy to the main lamp when saidterminals are con-- Li; nected with said source, and the other one orsaid circuits including a switch, and a thermal device responsive to theheat of themain lamp and operative to open said switch when the main

